In West German Pat. No. 1 527 465, there is disclosed a double pressure pin press having a reciprocating press carriage on which a punch carrier is swingably mounted, the punch carrier being oscillated by rotatable cam plates which cooperate with respective cam followers affixed to the punch carrier. The drive train to the cam plates includes a splined shaft disposed parallel to the direction of reciprocation of the carriage and reciprocable therewith, the plined shaft fitting within a complementarily splined sleeve which forms a part of one bevelled gear of a bevel gear set, such sleeve being fixed against axial movement.
In Austrian Pat. No. 132 512 there is disclosed a double pressure pin press having a reciprocating press carriage, the carriage bearing a punch carrier which is reciprocated in a direction normal thereto by diametrically opposed cam followers cooperating with a rotatably driven cam. The drive train for the rotatable cam includes a splined shaft and sleeve combination which is generally similar to that of German Pat. No. 1 527 465.
French Pat. No. 1,245,043 discloses a double pressure pin press having a reciprocating press carriage on which a punch carrier is swingably mounted. In this instance the cams for oscillating the swingable punch carrier are mounted on a fixed structure, connection between the cam followers which cooperate with such cams and the swingable punch carrier being effected by a link there between having universal joints at its opposite ends. The mechanism of this patent is cumbersome, complicated and expensive.
In both West German Pat. No. 1 527 564 and Austrian Pat. No. 132 512 the mounting for the plate cams and the splined connection in the drive train therefor occupy considerable space. Thus the splined cam shaft is mounted in two bearings on the carriage, and the plate cams have flanges of appreciable width. The splined connection must exceed in length the stroke of the carriage. The total length of the splined shaft requires that it be of a diameter which is larger than would be necessary by reason of torque requirements alone. This means that the dimensions of the bearings surrounding the splined shaft, the hub and the sleeve of the bevelled gear must also be larger. Added to this is the unavoidable wear on the engaging surfaces of the lands of the plined connection which have to take up and transmit the driving forces to the cam. Such wear is at a maximum in the extended or forward position of the carriage when the engaging surfaces of the lands on the splined shaft and the splined sleeve are in driving engagement throughout only a fraction of their splined lengths.